Collapse dynamics and runout of dense granular materials in a fluid

Vincent Topin (1) , Yann Monerie (2) , Frédéric Perales (2) , Farhang Radjai (1)

1 PMMG - Physique et Mécanique des Milieux Granulaires
2 MIST - Laboratoire de micromécanique et intégrité des structures

We investigate the effect of an ambient fluid on the dynamics of collapse and spread of a granular column simulated by means of the contact dynamics method interfaced with computational fluid dynamics. The runout distance is found to increase as a power law with the aspect ratio of the column and, surprisingly, for a given aspect ratio and packing fraction, it may be similar in the grain-inertial and fluid-inertial regimes but with considerably longer duration in the latter case. We show that the effect of fluid in viscous and fluid-inertial regimes is to both reduce the kinetic energy during collapse and enhance the flow by lubrication during spread. Hence, the runout distance in a fluid may be below or equal to that in the absence of fluid due to compensation between those effects.

Mots clés: granular matter; runout; fluid-grain interactions; contact dynamics; avalanche

Domaines: Mécanique des matériaux [physics.class-ph]; Mécanique des matériaux [physics.class-ph]

Vincent Topin, Yann Monerie, Frédéric Perales, Farhang Radjai. Collapse dynamics and runout of dense granular materials in a fluid. Physical Review Letters, 2012, 109, pp.188001. ⟨10.1103/PhysRevLett.109.188001⟩. ⟨hal-00689730⟩